A. Golf Ball Construction and Composition
Modern golf balls generally comprise plural layers, including a core and at least one additional outer layer. Ball performance can be substantially modified by changing the ball construction and/or chemical composition of one or more golf ball components. Chemical composition can be modified to vary, for example, polymer hardness, compression, resilience and/or durability.
B. Ionomers and Patent Publications Describing Particular Ionomer Compositions for Making Golf Balls
A number of issued United States patents disclose particular ionomer compositions ostensibly useful for making golf balls. Ionomers typically are copolymers that contain both nonionic repeat units and a small percentage, generally less than about 15%, of ion-containing repeat units. One example of an ionomer is the sodium or zinc salt of poly(ethylene-co-methacrylic acid), a copolymer derived from ethylene and methacrylic acid.
Non-polar chains of an ionomer group together, as do the polar ionic groups. As a result, ionomers have physical properties similar to crosslinked polymers or block copolymers, although ionomers are not crosslinked polymers in the traditional sense. When heated sufficiently to overcome the electrostatic forces that cause the ionic groups to cluster, ionomer polymer chains move more freely, resulting in a polymer having elastomeric properties and the processability of a thermoplastic. As a result, ionomeric polymers often are referred to as thermoplastic elastomers.
Ionomers initially were formed by fully or partially neutralizing carboxyl functional groups with metal cations. This method is exemplified by Yuki et al., U.S. Pat. No. 4,955,966, “Rubber Composition and Golf Ball Comprising It.” A brief historical review of the subsequent development of ionomers for use in golf balls is provided by Rajagopalan, U.S. Pat. No. 5,691,066, “Golf Ball Comprising Fluoropolymer and Method of Making Same,” and Dalton et al., U.S. Pat. No. 6,653,403, “Golf Balls Having a Cover Layer Formed from an Ionomer and Metallocene-Catalyzed Polyolefin Blend and Methods of Making Same.”
C. Patent Publications Describing Particular Compositions Comprising Amine Compounds Useful for Making Golf Balls
Particular amines, generally polyamines having two or more amine functional groups, have been used in compositions for making golf balls. For example, U.S. Pat. No. 5,484,870, entitled “Polyurea Composition Suitable for a Golf Ball Cover,” discloses reacting particular organic isocyanates with particular diamines, such as the following compound.
Certain patents discuss using melamine, often melamine-formaldehyde polymers, for making certain golf ball components, including U.S. Pat. Nos. 5,150,905, 5,985,370, 6,142,887, 7,208,546, 7,226,961, 7,261,647, and 7,314,896. The chemical structure for melamine is shown below.

Taylor Made Golf Company, Inc. (Taylor Made), the assignee of the present application, also has filed applications directed to compositions comprising ionomers and amine compounds that are useful for making golf balls. See, for example, U.S. patent application Ser. No. 10/845,3370, which published on Nov. 25, 2004, as US/2004/0236030-A1, and U.S. patent application Ser. No. 11/685,335, which published on Oct. 4, 2007, as US/2007/0232756-A1, both of which are incorporated herein by reference.